By Dave Harrold
An increasing number of companies are finding that carefully considering the human factor in operator interface and control room designs is contributing significantly to productivity and operational effectiveness.
What sets these companies and their control rooms apart from the control rooms most of us are familiar with is that only the people who need to be in them are there, and every aspect of these control rooms has been carefully considered to ensure that the operator maintains high levels of vigilance and situation awareness.
These control rooms are not the place where maintenance stops by to get a stale donut and cup of coffee; not the place where contractors line up to get hot-work permits; not the place where people drop off order forms for their kids cookie, candy bar and trash bag sales; not the place where people congregate and talk about last nights ball game. No, these control rooms exist for one thing and one thing onlyto operate the plant as efficiently and productively as possible. These control rooms are the operators equivalent of an air-traffic control center, and until you embrace that mindset, your plant will never achieve its full operational excellence potential.
Defining the Workplace
Be it poorly designed graphics, alarm overload or poor control room layout, there are numerous documented cases that validate that when human factors and ergonomics (fitting the workplace to the worker) are left out of design considerations, operators are frequently and unnecessarily distracted, often resulting in needless injuries, equipment damage, off-spec product and so forth. Eventually someone realizes that plant operations are performing less than optimally, and a costly retrofit project is initiated. But will the project produce the desired results?
Worsley Alumina Pty Ltd., Worsley, Western Australia, is among the growing list of companies that are realizing that fitting the workplace to the worker is key to achieving operational effectiveness.
Arnold Oliver, Worsleys superintendent of process control, says, We believe much of Worsleys success is the result of our engaging competent consultants and fully embracing a situation-awareness initiative that incorporated people, alarms, graphics, training and control room design. As a result of our attention to detail, our control room operators are now better informed and thus are making better decisions in less time.
The process Worsley described is a relatively new design concept known as human systems integration (HSI), and it is being effectively used by the U.S. Department of Defense and the National Aeronautics and Space Administration in the design of military battlefield and space travel systems. HSI incorporates a disciplined, unified and interactive approach to integrate human considerations (both cognitive and physical) into a design to improve total system performance and reduce injuries and costs of ownership. HSI incorporates manpower, personnel, training, safety and occupational health, survivability, habitability and human factors engineering.
Integral to the HSI process is applying human factors engineering/ergonomics (HFEE) to fit the work to the worker, instead of forcing the worker to adapt to existing working conditions.
Figure 1. ISO 11064 ergonomic design standards
One of the most vivid examples of a need to consider HFEE is in the control rooms of many process plants worldwide.
How often do you see a press release, brochure or magazine article celebrating a successful start-up that includes a photo of an operator sitting at the operator console? Most likely, the photo showed a bunch of monitors and keyboards plopped down on some computer furniture. What you didnt see was that the control room was built like a box, and then someone was tasked with fitting all the people, equipment, supplies and kitchen into it.
Operators need to be allowed to do what they are trained and paid to do and that requires that they be provided an environment that is void of as many unnecessary distractions and disruptions as possiblesomething akin to an air-traffic control center.
Whats the Goal?
The goal in designing a control room is to create a work environment that promotes the operators ability to maintain high levels of vigilance and situation awareness, says Ian Nimmo, founder and president of User Centered Design Services, and who one client describes as the godfather of situation awareness and alarm management.
Through the late 1970s, control rooms consisted of long panel boards with logically grouped recorders, controllers, indicators, switches, lights and alarm light boxes arranged to provide operators with a big picture of the process.
Beginning in the 1980s, the introduction of distributed control systems (DCS) shrunk those long panel boards into fifteen-inch monitors. To compensate for the operators loss of the big picture, additional monitors were added, along with lots and lots of DCS-based alarms. It was not uncommon for a process plant to evolve from 150 alarm light boxes to more than 2,000 DCS-based alarms.
The distributed architecture of the DCS also encouraged control room consolidation, thus replacing face-to-face conversations between the control room and field operator with sometimes less-than-reliable radio communication. Greater physical distance also changed how supervisors interacted with the control room and field operators. Combined, these changes resulted in the creation of an entirely different control room environment, and it was done with very little thought about its impact on operational performance. Whats truly sobering is that twenty-plus years later, many of those same problems continue to exist in control rooms worldwide.